Contrasting growth responses in lamina and petiole during neighbor detection depend on differential auxin responsiveness rather than different auxin levels
Contrasting growth responses in lamina and petiole during neighbor detection depend on differential auxin responsiveness rather than different auxin levels
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DOI：
10.1111/nph.13449
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发表时间：
2015-10-01
期刊：
影响因子：
9.4
通讯作者：
Fankhauser, Christian
中科院分区：
文献类型：
--
作者：
de Wit, Mieke;Ljung, Karin;Fankhauser, Christian
叶面遮荫触发特定结构的快速生长，促进植物直接接触阳光。在许多植物物种的叶片中，这种生长反应是复杂的，因为尽管遮荫触发了叶柄的伸长，但它减少了叶片的生长。相同的外部线索如何导致叶片不同部位的这些截然不同的生长反应尚不清楚。通过突变体分析、药物治疗和基因表达分析，我们研究了光敏色素相互作用因子7 （PIF7）和促生长激素生长素在这些叶片生长反应中的作用。叶柄伸长和叶片生长减少都依赖于PIF7。诱导生长素的产生是叶柄和叶面产生相反生长反应的必要和充分条件。然而，这些不同的生长反应不是由两个叶片中不同的生长素浓度引起的。我们的研究表明，生长素水平的短暂增加会触发不同叶片部位的组织特异性生长反应。我们提供的证据表明，这可能是由叶柄和叶片对生长素的不同敏感性和组织特异性基因表达引起的。
Foliar shade triggers rapid growth of specific structures that facilitate access of the plant to direct sunlight. In leaves of many plant species, this growth response is complex because, although shade triggers the elongation of petioles, it reduces the growth of the lamina. How the same external cue leads to these contrasting growth responses in different parts of the leaf is not understood. Using mutant analysis, pharmacological treatment and gene expression analyses, we investigated the role of PHYTOCHROME INTERACTING FACTOR7 (PIF7) and the growth-promoting hormone auxin in these contrasting leaf growth responses. Both petiole elongation and lamina growth reduction are dependent on PIF7. The induction of auxin production is both necessary and sufficient to induce opposite growth responses in petioles vs lamina. However, these contrasting growth responses are not caused by different auxin concentrations in the two leaf parts. Our work suggests that a transient increase in auxin levels triggers tissue-specific growth responses in different leaf parts. We provide evidence suggesting that this may be caused bythe different sensitivity to auxin in the petiole vs the blade and by tissue-specific gene expression.